Socket Set Buying Guide: Deep, Impact, 6pt vs 12pt & Drive Sizes

The right socket set comes down to four choices: drive size (1/4", 3/8", 1/2" or 3/4"), 6-point or 12-point, standard or deep sockets, and chrome hand sockets or impact sockets. For most workshop and automotive work a 3/8" set covers the everyday sizes, a 1/2" deep socket set handles wheel nuts and long studs, and anything going on an impact wrench needs impact-rated sockets. Here is how to work out which socket set suits your jobs.

Socket drive sizes: 1/4", 3/8", 1/2" and 3/4"

The drive size is the square hole in the back of the socket that fits your ratchet, breaker bar, torque wrench or impact wrench. Bigger drives carry more torque and fit bigger fasteners, but the tools get bulkier.

• 1/4" drive: small fasteners, electronics, trim, small engines and tight spaces. Light and compact, but not for high torque.
• 3/8" drive: the general-purpose size. Covers most engine-bay, machinery and assembly work in the mid-size range.
• 1/2" drive: automotive and general engineering work where more torque is needed: suspension, wheel nuts, larger bolts. Also a common drive size for cordless impact wrenches.
• 3/4" drive: heavy machinery, trucks, tractors and structural bolts, where the fasteners are large and the torque is high.

Many people start with a multi-drive set that combines 1/4", 3/8" and 1/2" sockets in one case, then add dedicated sets as their work demands. Adaptors let you step between drive sizes, but don't use a small-drive socket on a big-drive tool to undo something heavy.

6-point vs 12-point sockets

A 6-point (single hex) socket grips the flats of a hex nut or bolt rather than the corners. That makes it less likely to round off a tight, rusted or slightly worn fastener, and it is the standard shape for impact sockets.

A 12-point (bi-hex) socket has twice as many positions, so it slips onto a fastener more easily when you can only see or reach it at an awkward angle, and it needs less swing between positions. The trade-off is less grip on a stubborn or damaged fastener.

If you only buy one, 6-point is the safer all-rounder. 12-point sockets are handy as a second set for tight engine bays and for 12-point fasteners.

Standard vs deep sockets

Standard (regular or shallow) sockets are shorter, so they fit where clearance above the nut is limited and they keep the ratchet close to the work. Deep sockets are longer, so they reach nuts on long studs and threaded rod, spark plugs and recessed fasteners that a standard socket can't get over. A deep socket set is often the second set people buy once they find a bolt protruding too far for a regular socket.

Some sets, like the Teng 111pc kit, include both regular and deep sockets, which saves buying two sets for the common sizes.

Impact sockets vs chrome hand sockets

This is the choice that matters most for safety. Chrome hand sockets are made for ratchets, breaker bars and torque wrenches, which apply a steady load. An impact wrench delivers a rapid series of hammer blows, and chrome hand sockets are not made for that kind of load: they can crack or split, and the pieces can fly.

Impact sockets are designed for those shock loads. They are usually made from chrome molybdenum steel with a black finish rather than bright chrome, and impact sets often come with retaining rings and pins to hold the socket on the anvil. Rule of thumb: if it goes on an impact wrench, use an impact socket. Impact sockets can also be used on hand tools; the reverse is not true.

Some impact sets are sold as "dual" sockets. The Powerbuilt 1/2" Dr 30pc deep dual impact set is sold as a dual set for use on both impact and hand tools.

Metric vs imperial (AF)

Metric sockets are sized in millimetres (10mm, 13mm, 17mm and so on). Imperial sockets, often marked AF or SAE, are sized in fractions of an inch (1/2", 9/16", 3/4"). Most modern cars and machinery use metric fasteners, but older British and American vehicles and equipment often need imperial. If you work across both, a combined MM/AF set saves you guessing. Don't force a near-size socket from the other system; a loose fit is the fastest way to round a nut.

Set contents and storage: rails, cases and trays

Check what is actually in the set, not just the piece count. Sockets are the core, but many sets also count a ratchet, extension bars, a universal joint, adaptors and bits as pieces. If you already own good ratchets, a sockets-only set may be better value for the sizes you need.

• Clip rails: sockets on a rail are quick to grab and easy to see when one is missing. Good for a drawer or a van.
• Cases: a plastic or metal case keeps a full set, ratchet and accessories together for carrying to the job.
• Trays: foam or modular trays (such as Teng's TC-Tray system) sit in a tool box or roller cabinet drawer and show you at a glance what is out.

Socket sets compared

How to choose a socket set by job

Home workshop or first set

Start with a multi-drive metric set in a case, ideally with some deep sockets. The Teng 111pc set covers 1/4", 3/8" and 1/2" drive in both metric and AF, with 3/8" deep sockets, spark plug sockets, bits and accessories in a latching plastic case.

Cordless impact wrench, tyres and suspension

Get a 1/2" deep impact socket set. The Powerbuilt 30pc deep dual impact set is a 30-piece metric 6-point deep set rated for impact use. For a compact set on a rail, the Teng 10pc deep impact set covers 10-24mm, and the Japanese-made Koken 14208M covers 10-27mm with Koken's flat drive design.

Mechanics and machinery maintenance

A 3/8" deep socket set on a rail lives in the top drawer and gets used every day. The Koken RS3300M (8-19mm, 55mm long) and the Gearwrench 14pc (6-19mm) are both 6-point deep sets on rails. Add a 12-point set like the Teng 8pc 1/2in deep 12-point for awkward access.

Heavy equipment, trucks and farm machinery

Step up to 3/4" drive. For an impact wrench, the Teng 16pc 3/4in impact set has 19-38mm sockets, an extension bar, retaining rings and pins in a TC-Tray. For hand tools, the Koken 6201M comes with 22-60mm 12-point sockets, a 565mm ratchet, extensions, a hinge bar and a sliding T bar in a metal case.

Care and use tips

• Seat the socket fully on the fastener before applying load, and pull rather than push on the handle where you can.
• Never use chrome hand sockets on an impact wrench, and don't put a cheater bar on a ratchet; use a breaker bar.
• Inspect sockets for cracks, splits or a worn, rounded opening and retire damaged ones.
• Wipe sockets clean and dry after use and put them back on the rail or in the tray so missing sizes are obvious.

FAQ

What is the best deep socket set to start with?

For most people, a 3/8" drive 6-point metric deep socket set covering roughly 8-19mm handles the common sizes. If you use an impact wrench, make your deep set a 1/2" impact set instead.

Can I use normal sockets on an impact wrench?

No. Chrome hand sockets aren't designed for the hammering load of an impact wrench and can crack. Use sockets that are sold as impact sockets.

Can impact sockets be used with a ratchet?

Yes. Impact sockets work on hand tools. They are usually a little thicker than chrome sockets, so check clearance in tight spots.

Is a 6-point or 12-point socket set better?

6-point grips better and is less likely to round off a fastener, so it is the better first set. 12-point is easier to fit in tight spots.

What drive size socket set do I need for wheel nuts?

1/2" drive is the usual choice for car and light truck wheel nuts, and deep impact sockets are the common pick when using an impact wrench. Heavy vehicles may need 3/4" drive or larger.

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